Low-noise bladeless fan

ABSTRACT

A low-noise bladeless fan includes a base, a nozzle at the top of the base and noise-reduction components located within the base. The noise-reduction components include a first noise-reduction component, a second noise-reduction component and a third noise-reduction component. The first noise-reduction component is located at an interface between air outlets and an internal passage for airflow reduces noise by isolating, obstructing and separating noise created inside the outer casing. The second noise-reduction component is disposed within an impeller fixture reduces noise by absorbing noise created inside the outer casing. Through-holes are disposed in the bottom of the outer casing act as the third noise-reduction component and also reduce noise. The arrangement of noise-reduction components can reduce noise created in the fan, thereby cooling users with natural and soft wind.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of and priority to Chinese PatentApplication No. 201110234196.7, filed on Aug. 16, 2011, which is ownedby the instant application and the disclosure of which is incorporatedherein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to bladeless fan, and particularly relatesto a low-noise bladeless fan.

BACKGROUND OF THE INVENTION

Traditional fans are operated in such a way: an electric motor drivesblades to rotate so as to create wind and to speed up air flow in thesurrounding environment, for cooling and heat-relieving and ventilation.But such kind of traditional fans are prone to danger (e.g. some kidsmay put their fingers into a fan when they are not carefully watched andthereby would be hurt by the blades), including some hidden dangers, andare not easy to clean.

A type of bladeless fan device for creating airflow is disclosed in anpatent application, publication number CN10142478A, which eliminates theabove deficiencies in the traditional fans. Yet to meet the designingdemand of bladeless fan, the designer would design some abrupt changesin shapes or bosses at the connecting portion between the base forhousing an impeller and a nozzle, as a result, when flowing into theinternal passage for airflow in the nozzle through the air inlets of thebase, the airflow will pass by the abrupt changes or the bosses and thenthe resistance increases. And noise will be caused at the interfacebetween the air outlets and the internal passage for airflow under theaction of air shear forces and other acting forces. In addition, about90% of the interior space of the base is occupied by the impellerassembled; so there is only about 10% of the interior space of the baseavailable for airflow that flows into the outer casing. It is to say,the space provided by the duct for the airflow is the gap between theimpeller and the outer casing. When airflow flows into the air ducts, itwill give rise to loud whistlers due to abrupt change of its flowingpassage. Meanwhile the impeller will also create noise during itsoperation. The air inlets of the base, which are in communication withthe outside, are prone to being influenced from the externalenvironment. Dust, oil stain and the like from the external environmentare likely to come inside the fan through the air inlets during theoperation of the fan, which also cause more noise.

Further, bladeless fan devices are also disclosed in other patentreference documents, such as CN201568337U, KR100985378, HK1146191; butno solutions are raised to efficiently reduce the noise created in thebladeless fan.

SUMMARY OF THE INVENTION

In order to make up the deficiencies that rotating blades may hurtpeople and to lower the noise from the fan, the present inventionprovides a safe low-noise blades fan.

In order to have the above technical problem addressed, the presentinvention provides the following technical solutions:

A low-noise bladeless fan comprises a base provided with an impellerfixture and a nozzle located on the top of the base. The nozzlecomprises an internal passage for receiving airflow flowing through airoutlets and an air exhaust port. The internal passage is annular andforms a continuous loop or pipe within the nozzle. The air exhaust portcomprises a conical region tapered to an exit. As a component which isinternally hollow and having through-holes in its outer wall thereof,the impeller fixture contiguously or alternately surrounds the impellerand is in annular shape or other shape. There are noise-reductioncomponents are provided within the base, including a firstnoise-reduction component and a second noise-reduction component. Thefirst noise-reduction component is set on the inner wall of the outercasing, at the interface between the air outlets and the internalpassage for airflow, and in the space between the outer side of theimpeller and the inner wall of the outer casing. The firstnoise-reduction component is used for isolating, obstructing andseparating noise created in the outer casing during operation of thefan. The second noise-reduction component is set inside the impellerfixture for absorbing noise generated in the outer casing, with itsposition and shape fitting to the position and shape of the impellerfixture.

Preferably, the nozzle extends substantially orthogonally about the axisto define an opening. The opening has a shape which is circular in aninner track thereof and egg-shaped in an outer track thereof.

Preferably, the first noise-reduction component is trapezoidallydistributed from the outer casing to the air outlets along the innerwall of the outer casing, with the sectional area in the vicinity of theair outlets smaller than the sectional area in the vicinity of the airinlets. There is a gap between the first noise-reduction component andthe impeller.

Preferably, the second noise-reduction component is entirely orpartially filled inside the impeller fixture.

Preferably, the first noise-reduction component is made of steel plates,lead plates, brick walls or other materials of higher density.

Preferably, the second noise-reduction component is made of slag wool,blankets or other porous sound absorbing materials.

Preferably, the first noise-reduction component is made of one of thematerials or any combination of several of them.

Preferably, the second noise-reduction component is made of one of thematerials or any combination of several of them.

Preferably, the noise-reduction components further include a thirdnoise-reduction component which is through-holes disposed in the bottomof the outer casing. The third noise-reduction component is effective onenlarging the airflow into the fan and for reducing noise.

The present invention relates to a low-noise bladeless fan comprising afirst noise-reduction component, a second noise-reduction component anda third-noise reduction component. The first noise-reduction componentis located at the interface between the air outlets and the internalpassage for airflow can reduce noise by isolating, obstructing andseparating noise created in the outer casing during the operation of thefan. The second noise-reduction component disposed within the impellerfixture can reduce noise by absorbing noise generated in the outercasing. The through-holes disposed in the bottom of the outer casing actas the third noise-reduction component and also can reduce noise.Therefore, compared with the prior art, the present invention becomessafer by getting rid of the deficiency that people may be hurt byrotating blades and can remarkably reduce the noise created in the fan.

Other aspects and advantages of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, illustrating the principles of the invention byway of example only.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages of the invention described above, together with furtheradvantages, may be better understood by referring to the followingdescription taken in conjunction with the accompanying drawings. Thedrawings are not necessarily to scale, emphasis instead generally beingplaced upon illustrating the principles of the invention.

FIG. 1 is a side view of a low-noise bladeless fan of the presentinvention.

FIG. 2 is a structural schematic view of the low-noise bladeless fan ofthe present invention along an A-A cross-section.

FIG. 3 is a partial schematic view of the low-noise bladeless fan of thepresent invention.

DESCRIPTION OF THE INVENTION

FIG. 1 shows a side view of a low-noise bladeless fan 10 including abase 11 and a nozzle 12.

As shown in FIG. 2, the low-noise bladeless fan 10 comprises the nozzle12 located at the top of the base 11, and noise-reduction components 13located within the base 11.

As a major mounting assembly of the low-noise bladeless fan, the base 11can have an arced shape, a cylindrical shape, a cuboid shape or othershapes.

The base 11 comprises an outer casing 111, air inlets 112, air outlets113, air ducts 114 between the air inlets 112 and the air outlets 113,as well as an impeller 115 and an impeller fixture 116 accommodated inthe outer casing 111.

The outer casing 111 is a casing body with an opening at one endthereof, the opening being in communication with the nozzle 12. Theouter casing 111 has a shape designed based on actual design demand andnot confined to the present embodiment.

The air inlets 112 are a plurality of through-holes disposed on a sideface of the base 11 and run through the side wall of the outer casing111, for communicating airflows inside and outside the outer casing 111.The air inlets 112 in the present embodiment are uniformly distributedon one side of the outer casing 111. Of course, the air inlets 112 alsocan be distributed all over the entire side wall or the other side wallsof the outer casing 111. The detailed positions and distribution mannersnot confined to the present embodiment.

The air outlets 113 are located at the opening of the outer casing 111and are in communication with the nozzle 12 for delivering airflow tothe nozzle 12.

The air ducts 114 are located between the air inlets 112 and the airoutlets 113 to provide channels for the airflow that flows from the airinlets 112 into the outer casing 111. During operation, the airflowflows into the outer casing 111 from the air inlets 112 and flows alongthe air ducts 114 to the air outlets 113.

The impeller 115 located in the air ducts 114 is fixed inside the outercasing 111 by the impeller fixture 116, for increasing pressure of airthat flows from the air inlets 111 and delivering pressurized air to theair outlets 113.

The impeller fixture 116 is an internally hollow component withthrough-holes on its outer wall and encircles the impeller 115contiguously or alternately. The shape of the impeller fixture 116 couldbe annular shape or other shape, and in this preferable embodiment it isannular shape.

As shown in FIG. 3, the nozzle 12 comprises an internal passage 121 forreceiving the airflow from the air outlets 113 and an air exhaust port122 where the airflow is emitted. The nozzle 12 extends substantiallyorthogonally or circumferentially about the axis X to define an opening123 which could be in many shapes, such as a circular shape, anelliptical shape, a rounded rectangular shape, a partially annularshape, or other shapes. In the present embodiment, the inner track ofthe opening 123 is circular and the outer track is egg-shaped.

The internal passage 121 is annular and forms a continuous loop or pipethat located inside the nozzle 12.

The air exhaust port 122 comprises a conical region 1222 tapered to anexit 1221.

Air from outside the fan device is drawn by the airflow emitted from theair exhaust port 122 through the opening 123.

During the operation of the low-noise bladeless fan of the presentembodiment, airflow flows into the outer casing 111 from the air inlets112 and pass by the air ducts 114. After being pressurized by theimpeller 115, the airflow flows from the air outlets 113 into theinternal passage 121.

Due to the designing demand of the low-noise bladeless fan, noise willbe created when airflow flows into the internal passage 121 from the airinlets 113. As a result, there would be a first noise source 100 definedat the interface between the air outlets 113 and the internal passage121. The impeller 115 as shown in the figures occupies about 90% of thespace of the base 11, hence there would be only 10% of the space leftfor the airflow that flows into the outer casing 111; it is to say, thespace in the air duct 114 is the space in the casing 111 subtract thevolume of the impeller 115. When the airflow flows into the air ducts114 from the space encircled by the outer casing 111, large noise willbe created, plus, the impeller 115 would also create some noise; hereinthere would be a second noise source 101 defined. In order to reduce thenoise, in the present embodiment, noise-reduction components 13 are setin the base 11.

The noise-reduction components 13 comprise a first noise-reductioncomponent 131, and a second noise reduction component 132.

The first noise-reduction component 131 is disposed on the inner wall ofthe outer casing 111, and located at the interface between the airoutlets 113 and the internal passage 121, and in the space between theouter side of the impeller 115 and the inner wall of the outer casing111. The first noise-reduction component 131 is used for isolating,obstructing and separating the noise created in the outer casing 111during the operation of the fan. The first noise-reduction component 131is made of a material which reduces transmission sound energy from anincident sound source by reflecting the incident sound. The material isheavy and compact, free of pores or gaps and of a higher density (suchas, steel plates, lead plates, brick walls or other materials of ahigher density). The first noise-reduction component 131 mainlyfunctions to obstruct noise from being delivered from the inside of theouter casing 111 to the space outside the outer casing 111 by reflectingthe noise created in the space formed between the air ducts 114 and theair outlets 113 within the outer casing 111 (such as the noise createdduring operation of the impeller 115, the noise caused by the abruptchanges in the shape of the flow passage when airflow flows past theouter side of the impeller 115 or the connection portion between theouter casing 111 and the nozzle 12). Thereby the first noise reductioncomponent prevents the inference of the noise. As can be seen from theabove noise-reduction principle of the first noise-reduction component131, the effect of noise reduction by using the first noise-reductioncomponent 131 which is made from a soundproof material or of a soundproof configuration is much better than the effect of noise reduction byabsorbing sound. The first noise-reduction component 131 in the presentembodiment is disposed between the outer side of the impeller 115 andthe inner wall of the outer casing 111, at the connection portionbetween the outer casing 111 and the nozzle 12, with its shape matchingthe shape of the outer casing 111. The first noise-reduction component131 is trapezoidally distributed from the outer casing 111 to the airoutlets 113 along the inner wall of the outer casing 111, with thesectional area in the vicinity of the air outlets 113 smaller than thesectional area in the vicinity of the air inlets 112. There is a gapbetween the noise-reduction component 131 and the impeller 115.Preferably, the air ducts 114 are partially filled with the firstnoise-reduction component in the present embodiment.

The second noise-reduction component 132 is disposed within the impellerfixture 116 which is internally hollow and provided with through-holesin the outer wall thereof, with its position and shape matching theposition and the shape of the impeller fixture 116. The secondnoise-reduction component 132 is used for absorbing noise created in theouter casing 111. The second noise-reduction component 132 is made froma material which reduces transmission of the sound energy of an incidentsound source by absorbing the incident sound. The material comprises alarge quantity of porous sound-absorbing materials that areinterpenetrating and having micro-porous from the exterior to theinterior (such as: slag wool, blankets, or other porous sound-absorbingmaterials). The second noise-reduction component 132 mainly functions toabsorb the noise created in the space formed by the air ducts 114 andthe air inlets 112 within the outer casing 111 (such as, the noisecreated during the operation of the impeller 115, the noise caused bythe changes in the shape of the circulation space when airflow flowspast the outer side of the impeller 115 by the air inlets 112 or theairflow flows into the narrow air ducts 114 from a larger space in thelower portion of the base 11). The incidence of sound waves to thesurface of the second noise-reduction component 132 causes vibration ofair inside the micropores of the second noise-reduction component 132.Because of the friction resistance and the viscous resistance of air aswell as thermal conduction, the second noise-reduction component 132could convert a substantial portion of sound energy into heat. Thensound is absorbed, and the noise transfer from the inside of the outercasing 111 to its outside is obstructed. The inside of the impellerfixture 116 is partially or entirely filled with the secondnoise-reduction component 132. Preferably, the second noise-reductioncomponent 132 in the present embodiment is disposed within the hollowimpeller fixture 116 and has the hollow impeller fixture 116 entirelyfilled, with its shape matching the shape of the impeller fixture 116.

As the first noise source 100 is located at the interface between theair outlets 113 and the internal passage 121, if a porous secondnoise-reduction component 132 is used at the first noise source 100, thequickly flowing airflow at the interface can easily induce the secondnoise-reduction component 132 to block the impeller. In addition, someoil and dust would enter the fan from the air inlets 112; the poroussecond noise-reduction component 132 which sucks oil and dust and so onbecomes unable to reduce noise. As a result, in the present embodiment,the first noise-reduction component 131 which is rigid and firm is usedat the first noise source 100. Although the second noise source 101 isalso located in the air ducts 114, the impeller 115 creates some noiseas well. For a better noise-reduction effect, the rigid and firm firstnoise-reduction component 131 is utilized in the space between the outerside of the impeller 115 and the inner wall of the outer casing 111,while the porous second noise reduction-component 132 is utilized withinthe hollow impeller fixture 116.

If the second noise-reduction component 132 is used separately, noisereduction can be accomplished only by absorbing sound by thesound-absorbing material. Yet, due to the properties of the secondnoise-reduction component 132, only part of the noise passing throughthe second noise-reduction component 132 can be absorbed, and furtherpart thereof still can penetrate through the second noise-reductioncomponent 132. It is to say, in this condition, the noise from theoutside can't be effectively isolated. When the second noise-reductioncomponent 132 cooperates with the first noise-reduction component 131,the sound transmission loss caused by the first noise-reductioncomponent 131 is increased. It is to say, at the location of secondnoise source 101, cooperation between the second noise-reductioncomponent 132 and the first noise-reduction component 131 helps toincrease the sound transmission loss caused by the first noise-reductioncomponent 131.

The detailed principle of noise reduction lies particularly as follows:when airflow comes to the first noise source 100 from the base 11, thenoise therein can be reduced by the first noise-reduction component 131which is rigid and compact; when airflow comes to the second noisesource 102 from the air inlets 112, the first noise-reduction component131 cooperates with the second noise-reduction component 132, therebythe noise therein is considerably reduced.

The base 11 is in communication with and is prone to influence from theexternal environment. During the operation of the fan, it is possiblefor dust, oil stain and so on in the external environment to come intothe fan through the air inlets 112, which also may create some noise. Inorder to reduce the noise therein and meanwhile to enlarge the airflowinto the fan, it is also feasible to set third noise-reduction component133 in the bottom of the outer casing 111.

The third noise-reduction component 133 is through-holes disposed in thebottom of the outer casing 111.

The third noise-reduction component 133 is effective on both enlargingthe airflow into the fan and reducing noise. The diameter of thethrough-hole is relevant with the wavelength of sound waves which can becalculated according to the frequency and sound speed. The said data canbe measured by experiments. The principle of noise reduction of thethrough-holes is based on the frequency distribution curve of noise.When airflow flows past the through-holes, the frequency distributioncurve of noise will move towards the high frequency or the ultrahighfrequency so as to remarkably reduce the audible sound in the frequencydistribution curve, thereby abating the interference and damage to humanbodies.

Made of a rigid and compact material, the first noise-reductioncomponent 131 is difficult for airflow to pass through, thereby unableto increase the airflow volume into the entire fan through the bottom ofthe outer casing 111. As the bottom of the outer casing 111 is subjectedto dust, oil stain and so on, the second noise-reduction component 132is easily to block the impeller under the force of strong airflow. Inaddition, the porous second noise-reduction component 132 is possible tosuck the oil, dust and so on in the external environment and becomeunable to reduce noise. As a result, in the bottom of the outer casing111, it is appropriate to set a through-hole structure which iseffective on reducing noise and enlarging the input of airflow, ratherthan the first noise-reduction component 131 and the secondnoise-reduction component 132. This through-hole structure is the thirdnoise-reduction component 133.

Finally, it should be appreciated that the above embodiments areprovided only for illustrating, but not for limiting, the technicalsolutions of the present invention. Although the present invention hasbeen explained in detail in the above embodiments, those skilled in theart should understand that modification to or equivalent replacements ofthe present invention are allowed without departing from the spirit andscope of the present invention, and the appended claims are intended tocover all these modifications or equivalent replacements which fallwithin the sprite and scope of the present invention.

1. A low-noise bladeless fan, comprising a base provided with animpeller fixture and a nozzle located at the top of the base, wherein,the nozzle comprises an internal passage for receiving airflow throughair outlets and an exhaust port, the internal passage is annular andforms a continuous loop or pipe within the nozzle, the exhaust portcomprises a conical region tapered to an exit; being a component whichis internally hollow and provided with through-holes in the outer wallthereof, the impeller fixture contiguously or alternately surrounds theimpeller, with one of the possible shapes thereof being annular; withinthe base, noise-reduction components are set and comprise: a firstnoise-reduction component, and a second noise-reduction component.Wherein the first noise-reduction component is set on the inner wall ofthe outer casing, at the interface between the air outlets and theinternal passage, and in the space between the outer side of theimpeller and the inner wall of the outer casing, for isolating,obstructing and separating noise created inside the outer casing duringthe operation of the fan; the second noise-reduction component isdisposed within the impeller fixture, with its position and shapematching the position and the shape of the impeller fixture, forabsorbing noise created inside the outer casing.
 2. The low-noisebladeless fan as claimed in claim 1, wherein, the nozzle extendssubstantially orthogonally about the axis to define an opening, theopening having a shape which is circular in an inner track thereof andegg-shaped in an outer track thereof.
 3. The low-noise bladeless fan asclaimed in claim 1, wherein, the first noise-reduction component istrapezoidally distributed from the outer casing to the air outlets alongthe inner wall of the outer casing, with the sectional area in thevicinity of the air outlets smaller than the sectional area in thevicinity of the air inlets, and there is a gap between the firstnoise-reduction component and the impeller.
 4. The low-noise bladelessfan as claimed in claim 3, wherein, the first noise-reduction componentis made of steel plates, lead plates, brick walls or other materials ofa greater density.
 5. The low-noise bladeless fan as claimed in claim 4,wherein, the first noise-reduction component is made of one of thematerials or any combination of several of them.
 6. The low-noisebladeless fan as claimed in claim 2, wherein, the first noise-reductioncomponent is trapezoidally distributed from the outer casing to the airoutlets along the inner wall of the outer casing, with the sectionalarea in the vicinity of the air outlets smaller than the sectional areain the vicinity of the air inlets, and there is a gap between the firstnoise-reduction component and the impeller.
 7. The low-noise bladelessfan as claimed in claim 6, wherein, the first noise-reduction componentis made of steel plates, lead plates, brick walls or other materials ofa greater density.
 8. The low-noise bladeless fan as claimed in claim 7,wherein, the first noise-reduction component is made of one of thematerials or any combination of several of them.
 9. The low-noisebladeless fan as claimed in claim 1, wherein, the second noise-reductioncomponent is entirely or partially filled within the impeller fixture.10. The low-noise bladeless fan as claimed in claim 9, wherein, thesecond noise-reduction component is made of slag wool, blankets or otherporous sound-absorbing materials.
 11. The low-noise bladeless fan asclaimed in claim 10, wherein, the second noise-reduction component ismade of one of the materials or any combination of several of them. 12.The low-noise bladeless fan as claimed in claim 2, wherein, the secondnoise-reduction component is entirely or partially filled within theimpeller fixture.
 13. The low-noise bladeless fan as claimed in claim12, wherein, the second noise-reduction component is made of slag wool,blankets or other porous sound-absorbing materials.
 14. The low-noisebladeless fan as claimed in claim 13, wherein, the secondnoise-reduction component is made of one of the materials or anycombination of several of them.
 15. The low-noise bladeless fan asclaimed in claim 1, wherein, the noise-reduction components furthercomprise a third noise-reduction component which is through-holesdisposed in the bottom of the outer casing.
 16. The low-noise bladelessfan as claimed in claim 2, wherein, the noise-reduction componentsfurther comprise a third noise-reduction component which isthrough-holes disposed in the bottom of the outer casing.